The field of wireless communications is faced with pressure of explosive growth of data services. To increase a network capacity and reduce transmission costs, the industry has proposed a heterogeneous network (Hetnet) technology. A Hetnet is formed by cells of different sizes and different types, including macro cells and small cells. The small cells include cells in various forms such as a micro cell, a pico cell, a femto cell, and a remote radio head (RRH). In an area with dense traffic, deploying more small cells may effectively increase a network capacity in the area. In addition, because sizes of the small cells are small, and capital expenditures (CAPEX) and operating expenses (OPEX) of the small cells are both low, the Hetnet attracts attention of many operators, and is a major direction of wireless network evolution.
In the prior art, when small cells and macro cells are deployed on a same frequency, to reduce interference to a neighboring cell in an area in which coverage of a macro cell overlaps coverage of a small cell, a user equipment (UE) in a software handover area may add in advance the neighboring cell to an active set; in addition, cells in the active set may also be convenient for access of the UE, and there are relatively few handover signaling overheads.
In a process of implementing the foregoing interference coordination, the applicant finds that the prior art has at least the following problem: When the UE moves from a center of the small cell to an edge, signals of the small cell are attenuated abruptly, while signals of the macro cell become stronger slowly, and consequently, the UE cannot be handed over to the macro cell in time; in addition, in dense deployment of small cells, the UE may be frequently handed over between cells, resulting in a lot of handover signaling overheads.